1. Field of the Invention
The present invention relates to a method of manufacturing a non-reciprocal circuit device such as an isolator or a circulator.
2. Description of the Related Art
A non-reciprocal circuit device such as an isolator or a circular is used in, e.g., a mobile wireless device such as a mobile phone. This type of non-reciprocal circuit device is configured to accommodate a gyromagnetic component constituted of a soft magnetic substrate, a center electrode and others, a permanent magnet, a matching capacitor(s) and a terminating resistance in a case functioning as a yoke and an insulator as typified by, e.g., Patent References 1 and 2.
The gyromagnetic component, the permanent magnet or the like and the case are independent components. Therefore, it is a conventional general technique to manufacture these components in different processes and then incorporate the gyromagnetic component, the permanent magnet and electric components such as a matching capacitor or a terminating resistance in the case, thereby producing a non-reciprocal circuit device.
Meanwhile, a reduction in size has been endlessly demanded for this type of non-reciprocal circuit device because of its marketability. As means for responding to a demand for a reduction in size, as disclosed in, e.g., Patent References 1 and 2, there has been proposed a configuration in which a square soft magnetic substrate is used in place of a discoid soft magnetic substrate, this substrate is accommodated in a case having a square inner space and a capacitor or a terminating resistor is accommodated in a very dense state by utilizing a space between the soft magnetic substrate and a case inner wall surface.
However, even if such a configuration as disclosed in Patent References 1 and 2 is adopted, the case has been conventionally considered to be an essential constituent part in order to assuredly couple central constituent parts such as a gyromagnetic component or a magnet with each other, and hence there is a limit in a reduction in size.
Further, after the gyromagnetic component, the permanent magnet or the like and the case are produced in different processes, the gyromagnetic component, the permanent magnet and electric components such as a matching capacitor or a terminating resistor must be incorporated in the case to manufacture a non-reciprocal circuit device, there is also a limit in an improvement of mass productivity.
Patent Reference 1: Japanese Patent Application Laid-open No. 1999-205011
Patent Reference 2: Japanese Patent Application Laid-open No. 1999-97910